Pololu Robotics and Electronics is having its biggest Black Friday sale yet, discounting hundreds of sensors, actuators, motor controllers, and other robot parts by 30% to 60% and offering an additional 11% to 15% off orders over $100! Buy one Zumo Robot and get one free, save on a 3pi Robot and get a free programmer, and take advantage of great deals on select Arduinos, Raspberry Pis, and mbeds. The first doorbuster deals go live Wednesday, November 27, and the sale runs through Cyber Monday (December 2). For details, visit www.pololu.com/blackfriday
Controlling the blink rate of an LED — the 'hello world' equivalent in hardware — is the most common way of demonstrating how to program a microcontroller. Many microcontrollers have a free onboard LED — pin 13 on the Arduino, for example — that makes the task even simpler. While such applications are useful, LED technology has come a long way since LEDs were first used as relatively low intensity monochromatic on-off indicators.
In addition to SMT LEDs the size of a grain of sand, there are jumbo LEDs, super-bright compact LEDs, monochromatic LEDs in a variety of colors, and multicolor LEDs that can reproduce any color. Then, there are the monochromatic and color LED matrices. Some have onboard microcontrollers that support high level graphic and text libraries, much like LCD displays. Then there are the powerful LED laser diodes — often referred to as simply laser diodes — that produce monochromatic coherent light.
Based on activity in online forums, LED matrices are clearly generating the most buzz. My current favorite is the 1.2" 8x8 bicolor matrix with I2C backpack — that is, with onboard microcontroller — from Adafruit. At $16, the red/green LED matrix isn't cheap, considering an Arduino or Raspberry Pi sells for about $30. A less expensive option is a monochrome display ($10) which I've used, as well. If money is no object, Adafruit has a 1024 LED 32x32 color matrix panel ($120), but there's no onboard processor.
The smaller backpack-enabled LED matrices are a breeze to work with. There's no need to handle buffering, refresh rates, and relative PWM rates. As shown in the accompanying figure, all you need are power, ground, and two I2C leads from your microcontroller. The backpacks have address selection jumpers so that you can chain several matrices such as I did in the graphic. Most importantly, Adafruit offers an Arduino library that works across the monochrome and color 8x8 matrices.
Although I haven't used it, there's an impressive RGB 8x8 color LED matrix available from Parallax ($40). Not surprisingly, its backpack is based on the powerful Propeller chip. Unlike the bicolor LED matrices from Adafruit, the more expensive Parallax display uses RGB LEDs; meaning it can display millions of different colors. Another big plus for the Parallax matrix is that only one I/O pin is required. Parallax supports the matrix with libraries for the Arduino, BASIC Stamp, and Propeller chip.
If you want to experiment with a bare LED matrix and you have a microcontroller to dedicate to the project, the most economical option is probably an 8x8 red LED matrix from Seeed Studio ($2.25). Their large 2.5" bicolor 8x8 color LED matrix is also a good deal ($5.50), but expect to spend a lot of time programming.
So, what's the value in an LED matrix? They make great alphanumeric displays, for one. I use them — together with proximity detection sensors — to simulate eye tracking in humanoid-looking robots. I'm sure you can think of additional uses — from a colorful time display, with, say, red digits for pm and green digits for am, to mood lighting. NV
Allied Electronics (Allied), the trading brand of Electrocomponents plc (LSE:ECM), the world’s leading high service distributor of electronics and maintenance products, is now selling the latest innovative product to emerge from the Raspberry Pi Foundation. Priced at $26.95, the Pi NoIR infrared camera module is a variant of the existing visible light Raspberry Pi camera module stocked by RS since the end of last year, and features the same 5 megapixel image sensor as its predecessor with the optical light filter removed to enable IR light frequencies.
Developed for diverse applications including those requiring night vision (e.g. security and monitoring nocturnal animal behaviour), hyperspectral imaging, astronomy, and paranormal investigation, Pi NoIR is capable of taking still photos with a resolution of 2592 x 1944. The tiny module, which measures just 20mm x 25mm x 9mm, can also record up to 1080p HD videos at 30 frames per second, allowing users of Raspberry Pi models A and B to build video applications. The board will plug into the currently unused CSI pins on the Raspberry Pi, using the I²C interface for control.
To get started with Pi NoIR, users will need a Raspberry Pi board, an SD card with OS installed, and a battery pack or power supply. Optional extras include an infrared lamp, a Raspberry Pi camera stand, and various cables for HDMI, VGA and Ethernet connectivity. All components are available to purchase direct from Allied stock.
Trick or Treat? Got an arduino laying around? Here is a quick project from GreatScott! for your Jack-O-Lantern to scare those brats with a simple electronic circuit. It will light up and produce an annoying sound when someone gets to close. Code is also available for download. Happy Halloween Everyone!
The ability to add complex sound to a project — be it voice, music, or the chirping of angry birds — has never been so easy or affordable. Given the popularity of personal MP3 players, just about any song or sound imaginable can be downloaded from the Web. Although stand-alone versions of Seri aren’t yet available, large vocabulary voice synthesis options are no longer tied to expensive add-ons or desktop computers.
My current favorite for playing sequences of MP3 sounds is the Sparkfun MP3 player shield for the Arduino ($60), together with their 1.4W class D audio amp ($8), shown in the accompanying figure. I included the mechanical striker (or hammer) from a 50 year old piano for a size comparison, as well as a reminder of how far we’ve come in the production and reproduction of sound.
The mechanical striker is quite a piece of craftsmanship — there are multiple layers of felt, chucks of cork, leather, and carefully glued joints. It’s a one-of-a-kind, and — together with the wires and other components in an all-mechanical piano — creates a rich tone that can’t be fully reproduced on consumer-grade electronics.
The MP3 shield with an accompanying amp, in contrast, are stamped out in the thousands. Furthermore, MP3 files downloaded from the Internet sound the same on every shield. Some of the subtleties may be missing in the audio playback, but most people don’t notice.
I like the shield as a sound-effects source because of the ease with which MP3 files — stored on the onboard Flash drive — can be accessed and played. For headphones, it’s simply plug-and-play. However, if you need to drive an amp that isn’t configured for the low impedance audio output available from the headphone jack, then a pair of the 1.4W audio amps are a necessity (one amp for mono output). It’s possible to connect the MP3 player to a different amp, but I’d rather not bother with the capacitors and resistors needed to condition the output of the player.
I’ve also used the shield/amp combination with a small surface transducer (also available from SparkFun) that can transform a table top or plastic box into a speaker. You’ll have to add a resistor to the amp to increase the output of the amp so it drives the surface transducer to full output.
When it comes to voice, it’s hard to beat the price/performance of the Emic 2 text-to-speech module from Grand Idea Studio/Parallax ($60). The Propellerbased board — which is only 1.23” x 1.5” — supports nine voice styles in both English and Spanish. It uses the DECtalk text-to-speech engine to provide dynamic control for pitch, rate, and emphasis.
Last but not least, you should consider the Veho 360 speaker available from Parallax ($15). The golf ball sized speaker provides 2.4W of output for up to eight hours. It recharges in about four hours through a standard USB cable. Trouble is, I’m going broke giving these things to my nieces, nephews, and coworkers. Not only do they provide a simple, compact output for the SparkFun MP3 player and the Emic 2, but they transform a diminutive iPod into a boom box with amazing bass response. They also double as Christmas tree ornaments — something to consider in December. NV
Although small, the Key-Scope performs as a full functioning oscilloscope. You will receive the world’s smallest, high quality, low-cost oscilloscope realized in a key ring-type housing made in Italy. Priced below US$60, it serves as a useful gadget or gift to the electronics enthusiastic hobbyist. Since Key-Scope covers all major functions of a traditional oscilloscope, it also serves as a great tool supporting the electronics student to get familiar working with oscilloscopes.
Real-time Sampling Rate 1MSa/s
Analog Bandwidth100 kHz
Timebase Settings, 5us/div - 1h/div
Single Shot/Normal/Auto Mode
Also running Scroll & Data Logging Mode
Input Voltage selection from 10mV/div to 5V/div, 6 steps
Trigger Level Adjust
Zero Line Adjust
Features also Remote control via USB (data protocol published)
Simultaneous signal view on PC via USB
‘Key-Scope’ is our new developed digital storage oscilloscope for mobile measurement tasks and easy PC-Connection. The newly designed Key-Scope is based on the former released Wittig osziFOX initially offered in Germany 1993, also known in the US as the RadioShack ProbeScope Cat.No.: 22-310.
If you are interested in backing this project, visit the Kickstarter!
Introduction and demonstration of the JTAGulator, an open source hardware tool that assists in identifying on-chip debug (OCD) and/or programming connections from test points, vias, or component pads on a target device.
Galileo is a microcontroller board based on the Intel® Quark SoC X1000 Application Processor, a 32-bit Intel Pentium-class system on a chip (datasheet?). It’s the first board based on Intel® architecture designed to be hardware and software pin-compatible with Arduino shields designed for the Uno R3. Digital pins 0 to 13 (and the adjacent AREF and GND pins), Analog inputs 0 to 5, the power header, ICSP header, and the UART port pins (0 and 1), are all in the same locations as on the Arduino Uno R3. This is also known as the Arduino 1.0 pinout.
Galileo is designed to support shields that operate at either 3.3V or 5V. The core operating voltage of Galileo is 3.3V. However, a jumper on the board enables voltage translation to 5V at the I/O pins. This provides support for 5V Uno shields and is the default behavior. By switching the jumper position, the voltage translation can be disabled to provide 3.3V operation at the I/O pins.
Of course, the Galileo board is also software compatible with the Arduino Software Development Environment (IDE), which makes usability and introduction a snap. In addition to Arduino hardware and software compatibility, the Galileo board has several PC industry standard I/O ports and features to expand native usage and capabilities beyond the Arduino shield ecosystem. A full sized mini-PCI Express slot, 100Mb Ethernet port, Micro-SD slot, RS-232 serial port, USB Host port, USB Client port, and 8MByte NOR flash come standard on the board.
The Smoothie project is about creating a platform for controlling digital fabrication machines and to make that platform as useful to as many people, projects, and use cases as possible. While most current Open Source Hardware electronics use 8-bit AVR microcontrollers ( such as those used by Arduino ) Smoothieboard runs on a more powerful 32-bit ARM microcontroller ( LPC1768 Cortex-M3 ). This allows for smoother and faster step generation, as well as more precise math, deeper planning, and leaves room to add more features. It’s all Open Source but it’s also recent technology to help you get the most out of your machine.
The smoothie project is also about building great collaborative documentation for both users and for developers that is beginner-oriented and as exhaustive as possible. A lot more than is usual is there already on http://smoothieware.org and more is added all the time.
I consider myself in decent physical shape — I bike daily and have a regular lifting routine. Whenever I visit my younger sister on the west coast, she pulls out some DVD on advanced yoga or pilates or Bulgarian bag training, and puts me to shame.
The trouble is — without external nudging — I tend to stay in my comfort zone at the expense of learning something new. With neuromuscular training, if you don’t mix it up, you won’t grow.
It’s the same with technology. After I’ve spent months or years with a given microprocessor, I can usually do what needs to be done — even if it requires a few tricks here and there. Why invest the energy learning something new? In my case, it’s simple. I need to keep up with the latest wave of microcontrollers, sensors, and other devices to do my job as editor.
It turns out that getting out of my comfort zone inevitably introduces me to techniques that I can bring back to my favorite microcontroller or analog chip set.
What about you? Lacking external pressure to leave your comfort zone puts the motivation completely in your own hands. If you’re proficient at cranking out circuits with discrete logic chips, why bother learning to program the PIC or a Raspberry Pi? Conversely, if you’re a wiz at the Arduino, why bother with stand-alone A/D converter chips and high performance analog chips?
Well, I’m confident that you’ll likely learn something worthwhile as you grope around uncharted technology landscapes.
Continuing with the example of an onboard A/D converter in microcontrollers, let’s say you want to create an effects filter for a microphone or instrument pick-up. You could simply feed the audio signal to the A/D port of an Arduino. Once you’ve captured the signal, you could devise any number of digital filters to enhance or distort the signal before sending it out to an audio amp.
Of course, your filter design would be limited by the processing power and memory of the microcontroller. You might waste much of your microcontroller’s filter capabilities by creating the equivalent of a low-pass filter — something easily and inexpensively done in the analog world with a capacitor and resistor.
Or, if you’re after a distortion sound effect, you could do most of the work with a diode and resistor on the input of the A/D converter.
There’s also the issue of noise. Laying out a microcontroller board doesn’t take much forethought if you’re making a blinking LED controller. There’s input and output and power. Most often, experimenters with limited analog experience pay little attention to how the signals get where they’re supposed to go.
However, if your expertise includes analog audio circuits, you know that signal routing is critical to minimize noise pickup — whether from the 60-cycle power mains, a poorly regulated power supply, or from capacitive coupling of the signal output to the input.
Someone versed in analog audio circuit design will consider adding a ground plane in the form of, for example, a third layer in a printed circuit board to keep input and output coupling to a minimum, and ample use of bypass capacitors on the microcontroller power input leads and analog components. They might also consider using a pre-amp and dedicated high resolution/low noise A/D converter chips instead of the relatively modest A/D circuitry in the microcontroller.
So, from a practical perspective, how do you get out of your technological comfort zone? One way is to scan through this issue of Nuts & Volts and try your hand at a project that you’d typically skip because it’s not in your area of expertise.
The best way, of course, is to team up with someone who is both comfortable in his or her technological area and uncomfortable in yours. You’ll both expand your comfort zones and, as a bonus, get a bit of practice mentoring — a great skill to develop. NV
This time, learn how to connect your microcontroller to the software to plot a single channel of analog data. Plus, see how to scale raw ADC data into corresponding voltage levels so you don’t have to do math inside your micro. Read More...
Sweep generators have a lot of uses in the design, prototyping, and troubleshooting of amps, filters, and other circuitry. I wanted one that could speed up these tasks by presenting several parameters at the same time. This is the unit I came up with. Read More...